JP2014110678A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform such an operation that restriction on a rotation frequency is alleviated within a range that does not exceed a rated temperature of a fan motor without providing a temperature detector to the fan motor, in an air conditioner protecting the fan motor from overheat by providing an upper limit value to the rotation frequency of the fan motor.SOLUTION: Setting data that defines a control method for performing overheat protection for each ambient temperature is preliminarily stored. The control is performed so that an operation for permitting a rotation frequency of a fan motor to the maximum rotation frequency, or an operation for restricting the rotation frequency of the fan motor at the most to a predetermined upper limit value lower than the maximum rotation frequency, depending on an ambient temperature upon operation start and a time from the operation start.

Description

The present invention relates to overheat protection for a fan motor used in an indoor unit of an air conditioner.

Various devices using a motor are operated so that the rated temperature of the motor is not exceeded when the motor is incorporated in the device. However, if the motor speed is increased, the amount of heat generation increases, and if the motor speed is decreased. Since the amount of heat generation is reduced, when the motor is used at the maximum speed of the motor performance, if the rated temperature cannot be satisfied even if heat dissipation measures are taken, the motor speed is limited and rated. In some cases, overheat protection is performed to meet the temperature.

FIG. 1 is a characteristic diagram of temperature and time for explaining a test example of the upper limit value of the rotation speed of the motor. FIG. 1A shows a temperature change that occurs over time when a motor having a rated temperature of 90 ° C. is operated in an environment having an ambient temperature of 40 ° C. at a maximum rotation speed of 1500 rpm. In this example, the temperature that was 40 ° C. at the time of starting the motor suddenly rises with time, exceeds the rated temperature at the time indicated by the point T, and then continues to rise gradually until the temperature rise becomes saturated. It turns out that it is necessary to limit the number of rotations of the motor so as to satisfy the rated temperature and to perform overheat protection.

FIG. 1B shows the time when a motor having a rated temperature of 90 ° C. is operated at 1200 rpm, which is lower than the maximum rotation speed of the motor, in an environment where the ambient temperature is 40 ° C. as in FIG. The temperature change which arises with progress of is shown. In this example, although the motor temperature rapidly rises with time, the temperature rise is saturated before reaching the rated temperature, so that it can be seen that the rated temperature can be satisfied under this condition where the rotational speed is limited.

There is a device that performs the test as shown in FIGS. 1 (A) and 1 (B) and protects the motor from overheating so that the rated temperature is not exceeded by providing a uniform upper limit for the number of rotations of the motor. Even when used in an environment of 30 ° C lower than the upper limit temperature of 40 ° C, overheating protection is performed based on the use at the upper limit temperature of 40 ° C. The lower the temperature, the lower the motor speed limit that was not necessary, and the ability of the motor could not be fully utilized.

Against this background, a motor overheat protection device has been proposed that can bring out the capabilities of the motor more. (For example, refer to Patent Document 1). In addition, an air conditioner that protects the inverter and the motor by switching the overcurrent detection level of the compressor and limiting the rotation speed has been proposed. (For example, refer to Patent Document 2). Further, a temperature protection control device that suppresses the temperature rise of the motor without stopping the motor has been proposed. (For example, refer to Patent Document 3).

JP 11-355959 A (page 3, FIG. 3) Japanese Patent Laying-Open No. 2005-308233 (page 4, FIG. 2) JP 2008-104299 A (pages 5-6, FIG. 9)

Patent Documents 1 to 3 are techniques for operating the motor at maximum rotation while protecting the motor overheat. Patent Document 1 describes a stator coil end or stator core end surface of a rotating electrical machine, and Patent Document 2 describes a compressor. In addition, Patent Document 3 is realized by providing a motor with temperature detection means, and detecting the temperature of the motor. However, when the techniques of Patent Documents 1 to 3 are applied to a fan motor of an air conditioner, there is a problem that a temperature detection unit must be newly provided, resulting in an increase in cost.

The present invention solves the above-mentioned problems and relaxes the rotational speed limit without detecting the temperature of the fan motor for an air conditioner that provides a uniform upper limit value for the rotational speed of the fan motor and performs overheat protection. It aims at providing the air conditioner which can do.

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention includes a fan, a fan motor that drives the fan, an ambient temperature detection unit that detects ambient temperature, a time measuring unit, In the air conditioner including the control unit for controlling each of the above, the control unit takes in the ambient temperature when starting the fan motor, and when the ambient temperature is less than a predetermined temperature, the rotation number of the fan motor is When the maximum rotational speed of the fan motor is permitted and the ambient temperature is equal to or higher than the predetermined temperature, the rotational speed of the fan motor is permitted to the maximum rotational speed for a first predetermined time that is predetermined according to the ambient temperature. The upper limit of the rotational speed of the fan motor is limited to an upper rotational speed lower than a predetermined maximum rotational speed of the fan motor after the first predetermined time has elapsed. To.

Further, in the invention according to claim 2 of the present invention, the timing unit counts a stop time until the fan motor is started after the fan motor stops, and the control unit determines that the stop time is a second predetermined time. In the following case, the rotation speed of the fan motor is limited to an upper limit rotation speed lower than a predetermined maximum rotation speed of the fan motor when the fan motor is started.

According to the air conditioner of the present invention, it is possible to perform control utilizing the ability of the maximum rotation speed of the fan motor according to the ambient temperature when the operation is started without detecting the temperature of the fan motor. The time from the start of operation to the set temperature can be shortened as compared with the conventional air conditioner in which a uniform upper limit value is set for the rotational speed.

It is a temperature-time characteristic diagram explaining the test example of the rotation speed upper limit of a motor. It is a block diagram which shows the air conditioner of this invention. It is explanatory drawing which showed the temperature change of the fan motor according to ambient temperature. It is explanatory drawing explaining the setting data used for the overheat protection of the fan motor by this invention. It is a flowchart which shows the process which selects the driving | operation regarding the overheat protection of the fan motor by this invention. It is a flowchart which shows a process when the permission time is reached | attained from the driving | operation which permitted the maximum rotation speed of the air conditioner by this invention. It is explanatory drawing explaining the effect in the overheat protection control of the air conditioner by this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail as examples based on the accompanying drawings. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present invention.

FIG. 2 is a block diagram showing the air conditioner of the present invention. In FIG. 2, the air conditioner 1 includes a fan 10 that sends out the heat-exchanged air to the outside of the air conditioner 1, a fan motor 11 that drives the fan 10, a timing unit 12 that measures time, and a user operation. A communication unit 13 that communicates with a remote controller (not shown), an ambient temperature detection unit 14 that detects the ambient temperature of the air conditioner 1, a storage unit 15 that stores setting data relating to overheating protection of the fan motor, and the like. A control unit 16 for controlling is provided.

With such a configuration, the air conditioner 1 of the present invention receives the operation start instruction from the user who operates the remote controller via the communication unit 13, and when the fan motor 11 is activated, the ambient temperature detection unit 14 An ambient temperature is detected and the operation | movement which permitted the rotation speed of the fan motor 11 to the maximum rotation speed is started. Then, referring to the setting data in the storage unit 15 according to the detected ambient temperature, the time during which the operation that always permits the rotation speed of the fan motor 11 to the maximum rotation speed or the operation that permits the rotation speed to the maximum rotation speed by the timer unit 12 is performed. Time is measured, and after a predetermined time has elapsed, an operation is performed in which the upper limit of the rotational speed is limited to an upper rotational speed lower than the maximum rotational speed. The details of the setting data regarding the overheat protection of the storage unit 15 will be described later.

FIG. 3 is an explanatory diagram showing the temperature change of the fan motor according to the ambient temperature when starting the fan motor. The graph in FIG. 3 shows temperature on the vertical axis and time on the horizontal axis, and the temperature change when the fan motor with the rated temperature of 90 ° C and the maximum rotation speed of 1500rpm is started at the ambient temperature of 40 ° C and kept running at 1500rpm. The curve a shows the temperature change when the same fan motor was started at an ambient temperature of 30 ° C. and continued to operate at 1500 rpm, and the temperature change was indicated by a curve b. The same fan motor was started at an ambient temperature of 20 ° C. and continued to operate at 1500 rpm. The change in temperature over time is shown by curve c. Also, the temperature slightly lower than the rated temperature of the fan motor, 90 ° C (for example, the difference in temperature rise that occurs during the delay time from when the fan motor is instructed to reduce the rotational speed to when the rotational speed actually decreases) Considered 88 ° C.) is indicated by X ° C. As a precondition for the graph of FIG. 3, it is assumed that the ambient temperature and the fan motor temperature coincide.

Curve a in the explanatory diagram shows that the temperature of the fan motor rises and exceeds the rated temperature as the operating time elapses. Therefore, when the fan motor is started when the ambient temperature is 40 ° C., it is necessary to limit the rotational speed. Since the elapsed time to reach X ° C is Ta, even if it is driven at the maximum rotation speed from start to Ta, the rated temperature is not exceeded by limiting the rotation speed from the timing when Ta is reached. The time during which the maximum number of revolutions can be allowed can be determined within the range. Similarly to the curve a, the curve b also exceeds the rated temperature as the operation time elapses, and the temperature of the fan motor rises. Therefore, when starting the fan motor when the ambient temperature is 30 ° C., the curve b is set to the same X ° C. Tb, which is the elapsed time until it reaches, is the time during which the maximum number of revolutions can be permitted within a range not exceeding the rated temperature. Curve c does not exceed the same X ° C even after the operation time has elapsed, and the temperature rise of the fan motor is saturated. Therefore, when the fan motor is started when the ambient temperature is 20 ° C, the maximum rotation It turns out that driving with numbers can be continued. In the present invention, the temperature change of the fan motor for each ambient temperature is measured in advance by a test, so that the time during which the fan motor can be driven at the maximum rotation speed is determined according to the ambient temperature.

FIG. 4 is an explanatory diagram for explaining setting data used for overheating protection of the fan motor according to the present invention. This setting data is created based on the measurement result of the test described with reference to FIG. 3, is stored in advance in the storage unit 15 provided in the air conditioner 1 of FIG. 2, and is referred to by the control unit 16 when starting the fan motor.

The setting data items are `` ambient temperature '' which is the ambient temperature when the fan motor starts up, and the maximum value determined by the measurement result of whether the rated temperature is reached when the fan motor is driven at the maximum rotation speed from that ambient temperature. It consists of the “time limit necessity” for driving by the number of revolutions and the “permitted time” for driving by the maximum number of revolutions determined by the measurement result of the elapsed time until reaching X ° C. The range of this setting data is time From the maximum temperature that does not require restriction to the maximum temperature that is assumed as the usage environment of the air conditioner. 4 shows setting data in which the initial temperature from 20 ° C. to 40 ° C. is set in increments of 5 ° C. For example, when the ambient temperature is 27 ° C., the same ambient temperature exists in the setting data. Therefore, in order to make the drive at the maximum number of rotations longer, the setting data subdivided based on the measurement results of many ambient temperatures is used. It is desirable to create.

FIG. 5 is a flowchart showing a process of selecting an operation related to overheating protection of the fan motor according to the present invention. As a condition for starting the processing of FIG. 5, it is assumed that the communication unit 13 provided in the air conditioner 1 has received an operation start signal from the remote controller. Note that ST described in the flowchart represents a step, the number following the ST represents a step number, Y represents Yes, and N represents No.

When the control unit 16 receives an operation start signal from the remote controller via the communication unit 13, the control unit 16 detects the ambient temperature from the ambient temperature detection unit 14 and uses it for overheating protection of the fan motor rotation speed stored in the storage unit 15. Refer to items according to the ambient temperature detected from the data (ST1).
. Subsequently, it is confirmed whether or not a predetermined time (for example, 30 minutes until the fan motor 11 reaches the same temperature as the ambient temperature after the operation stop) has elapsed since the previous operation stop time stored in the storage unit 15. (ST2). The predetermined time described in ST2 is the second predetermined time of the present invention.

  When the second predetermined time has elapsed in ST2 (ST2-Y), the control unit 16 determines whether or not the “necessity of time restriction” item of the ambient temperature referenced from the setting data is “unnecessary”. Confirm (ST3). When the item “Necessity of time restriction is necessary” is “unnecessary” (ST3-Y), an operation that always allows the fan motor to the maximum number of rotations is selected (ST4). Then, the process ends.

In ST3, when the “necessity of time restriction” item of the ambient temperature is not “unnecessary” in ST3 (ST3-N), the control unit 16 selects an operation that permits the fan motor to the maximum number of revolutions for a predetermined time (ST5). ). Then, the countdown is started by the timer of the time measuring unit 12 using the referred permission time as a start value (ST6). Then, the process ends. Note that the permission time referred to in ST6 is the first predetermined time of the present invention. Further, when the countdown is completed, the time measuring unit 12 notifies the control unit 16 of an interrupt signal indicating the completion of the countdown.

In ST3, when the second predetermined time has not elapsed (ST2-N), the control unit 16 selects an operation limited to a predetermined upper limit rotational speed lower than the maximum rotational speed (ST7). Then, the process ends. Then, the selected operation is started.

FIG. 6 is a flowchart showing the processing when the permitted time is reached from the operation in which the maximum number of rotations of the air conditioner according to the present invention is permitted. As a condition for starting the processing of FIG. 6, the time measuring unit 12 provided in the air conditioner 1 finishes the countdown of the permitted time permitting the maximum rotation speed described in FIG. 5, and notifies the control unit 16 of the interrupt signal of the countdown end. Shall be. Note that the alphabets and numerals described in the flowchart are the same as those in FIG.

When the timer 16 is notified of the end of the countdown of the permitted time for permitting the maximum number of revolutions from the time measuring unit 12, the control unit 16 determines a predetermined upper limit number of revolutions lower than the maximum number of revolutions from the operation that allows the fan motor 11 to the maximum number of revolutions. (ST11). And it is confirmed whether it is operating exceeding the upper limit number of rotations of the operation which switched fan motor 11 at that time (ST12). When operating exceeding the upper limit rotation speed of the switched operation (ST12-Y)
Then, the fan motor 11 is requested to limit the rotation speed of the fan motor to the upper limit rotation speed of the operation (ST13). Then, the process ends. In ST12, when the operation is not performed exceeding the upper limit number of rotations of the switched operation (ST12-N), the process is terminated. In addition, the control part 16 which complete | finished this process continues the driving | operation restrict | limited to the predetermined upper limit rotation speed lower than the maximum rotation speed.

FIG. 7 is an explanatory diagram for explaining the effect in the overheat protection control of the air conditioner according to the present invention. In the explanatory diagram of FIG. 7, the horizontal axis shows the passage of time from the start of operation of the air conditioner to the stop of operation, and the conventional fan motor rotation speed is always limited to a rotation speed lower than the maximum rotation speed or less. The overheat protection pattern is “X”, the overheat protection pattern of the present invention, which always allows the maximum fan motor speed to be “Y”, and the fan temporarily for a predetermined time according to the ambient temperature from the start of operation. “Z” is another overheat protection pattern of the present invention that allows the motor rotation speed to the maximum rotation speed, and the fan motor rotation speed state in each pattern and the operation start at the time of heating and cooling according to the state The change in the room temperature from the room temperature to the set temperature is shown by curves “X”, “Y”, and “Z” on the graph. Further, in the pattern “Z”, the timing at which the rotation speed of the fan motor is switched from, for example, an upper limit of 1500 rpm to an upper limit of 1200 rpm is indicated by a broken line as a P point.

In addition, in the heating operation, the room temperature is 10 ° C. and the set temperature is set to 23 ° C. In the cooling operation, the room temperature is 33 ° C. and the set temperature is set to 27 ° C. The time to reach the set temperature by the operation of the pattern “X” is indicated by “Ty” and “Tz”, the time to reach the set temperature by the operation of the patterns “Y” and “Z” in the same way as “Tx”. ing. FIG. 7 shows changes in the room temperature when operating at the rotation speed of the fan motor that is the upper limit in the operation from the start of operation until the set temperature is reached.

First, changes in room temperature during heating operation will be described. In the pattern “X”, since the rotational speed of the fan motor is always limited to a predetermined upper limit (1200 rpm), the room temperature rises more slowly than in the other patterns, and the time “Tx” to reach the set temperature is the longest. In the patterns “Y” and “Z”, the fan motor is operated at the maximum speed (1500 rpm) until the point P is reached, so the room temperature rises faster than the pattern “X” and exceeds the point P. However, in the pattern “Y” in which this operation is continued, the time “Ty” for reaching the set temperature is the shortest. In addition, the pattern “Z” that limits the rotational speed of the fan motor to a predetermined upper limit value (1200 rpm) at the point P is more gradual than the pattern “Y” because the room temperature rise after the point P is exceeded. The time “Tz” to reach “Ty” is longer than “Ty” and shorter than “Tx”.

Next, the change in room temperature during the cooling operation will be described. In the pattern “X”, the room temperature gradually decreases as compared with the other patterns, and the time “Tx” for reaching the set temperature is the longest. In the patterns “Y” and “Z”, the room temperature drops earlier than the pattern “X” until the point P is reached, and the fan motor is operated at the maximum speed (1500 rpm) even if the point P is exceeded. The time “Ty” for reaching the set temperature of the pattern “Y” is the shortest. In addition, the pattern “Z” that limits the rotational speed of the fan motor to a predetermined upper limit value (1200 rpm) at the point P becomes a slower temperature drop than the pattern “Y” after the point P is exceeded. The reaching time “Tz” is longer than “Ty” and shorter than “Tx”.

As described above, in the overheat protection control of the fan motor according to the present invention, the rotation speed of the fan motor is permitted up to the maximum rotation speed according to the ambient temperature at the start of operation. The time to reach can be shortened. In the graph of FIG. 7, the example in which the pattern “Y” reaches the set temperature in a shorter time than the pattern “Z” has been described. However, when the room temperature approaches the set temperature, the rotational speed of the fan motor is increased step by step. When the lowering control is performed, the set temperature may be reached in the same time.

DESCRIPTION OF SYMBOLS 1 Air conditioner 10 Fan 11 Fan motor 12 Timekeeping part 13 Communication part 14 Ambient temperature detection part 15 Memory | storage part 16 Control part

Claims (2)

  An air conditioner including a fan, a fan motor that drives the fan, an ambient temperature detection unit that detects an ambient temperature, a time measurement unit, and a control unit that controls each of the air conditioner, wherein the control unit includes the fan motor When the ambient temperature is less than a predetermined temperature, the fan motor is allowed to rotate up to the maximum number of rotations. When the ambient temperature is equal to or higher than the predetermined temperature, the ambient temperature is The predetermined first predetermined time is allowed to allow the rotational speed of the fan motor to the maximum rotational speed, and the upper limit of the rotational speed of the fan motor is predetermined after the first predetermined time has elapsed. The air conditioner is limited to an upper limit rotational speed lower than the maximum rotational speed of the fan motor. The timer counts a stop time until the fan motor is started after being stopped, and the control unit is configured to start the fan motor when the fan motor is started when the stop time is equal to or shorter than a second predetermined time. 2. The air conditioner according to claim 1, wherein the rotational speed of the air conditioner is limited to a predetermined upper rotational speed that is lower than a predetermined maximum rotational speed of the fan motor.

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